i've heard it is but i'm not sure. i'm pretty sure if aluminum is safe to eat out of and cook with, it'd be safe with your lungs. but i don't know i'm not an expert on the subject. my piece has thin copper wire wrapped into an egg shape stuffed in the part of the bowl on my homemade bong that you don't put weed in (where the smoke goes through) and i've heard that's toxic...but hey that's what the water's for, right?